I'm looking for a story I think I read on here years ago. There were two girls in class and one offended the other or something, so the teacher let the one who was offended torture the other as punishment. She took her to a different room and tied her to a chair. The parts I remember was stabbing the underside of her breasts with an ice pick and breaking some of her fingers, but I think there was more. It was mostly consensual, the other girl didn't fight back at all. It read like it was part of a larger story universe, but I don't remember reading anything else of it.